1. Field of the Invention
The present invention relates to a coating method, a coater, and a method for manufacturing a planographic printing plate, and particularly relates to a coating method for applying a plurality of coating liquids onto a support in layers, a coater, and a method for manufacturing a planographic printing plate.
2. Description of the Related Art
In recent years, techniques to give various kinds of functions to a support by applying a plurality of coating liquids onto the support continuously traveling to form a multilayer film have been widely used. In the techniques to form such a multilayer film, it is necessary to prevent unintended generation of inter-layer mixing in the coating liquids applied in layers.
Conventionally, various kinds of proposals have been made as this kind of the technique. Japanese Patent Application Laid-Open No. 2005-334705 has described a method in which a plurality of components that increase viscosity of a coating liquid when the coating liquids simultaneously applied contact each other or mix with each other are added to one of the coating liquids simultaneously applied, thereby to prevent generation of inter-layer mixing. This method needs a set zone device for adding the components, which are essentially unnecessary, to increase the viscosity.
Japanese Patent Application Laid-Open No. 2002-049121 has described a method for coating a heat developing photosensitive material. According to the method, drying as soon as possible after stratified coating is preferable, and it is preferable to proceed to a drying step within 10 seconds in order to avoid inter-layer mixing attributed to flow, diffusion, density difference, and the like. Moreover, Japanese Patent Application Laid-Open No. 2001-113226 has described a method for manufacturing an information recording material formed by laminating at least two or more layers on a support. In the method, curtain coating of a coating layer consisting of multiple layers of coating liquid layers is performed on a part or all of the layers that form the information recording material, and the coating layer is dried within 2 minutes after coating. In these methods, it is necessary to arrange a coater close to a dryer since the time until it proceeds to the drying step is limited. For that reason, flexibility is limited with respect to arrangement of each apparatus in a manufacturing line.